Passage Speed

[Bash]

For planning purposes, I've had good luck with .7 x theoretical hull speed. For my boat, that gives me a 6.2 knot average passage speed, which comes in just under 150nm per day.

[Tropic Cat]

Originally Posted by 44'cruisingcat

.....And most of the trip conditions didn't suit fast sailing for us - we had 30+ knot winds for all but the first day, so we slowed down to around 6 knots for comfort's sake. We certainly weren't racing..

Finally some sanity.

I'll freely admit that I own a catamaran because it was the way to get my admiral participating in sailing. If the boat leans she won't go near it. Now that the years have rolled by I appreciate the comfort of my boat more and more as do all the monohull sailors in my marina.

When there's a group activity guess which boat we use?

If you're younger than 40 years old, buy that Dragonfly 920x. You can trailer it home each night and whiz around the course on Friday night....but good luck getting your admiral to go camping on it. And the only cruising you'll do is in your truck while traveling to your outboard repair guy.

[44'cruisingcat]

Originally Posted by Tropic Cat

Finally some sanity.

I'll freely admit that I own a catamaran because it was the way to get my admiral participating in sailing. If the boat leans she won't go near it. Now that the years have rolled by I appreciate the comfort of my boat more and more as do all the monohull sailors in my marina.

Interesting point. On the Vanuatu trip, not one of the 5 monohulls skipper's wives made the crossing. Not ONE. Of the 3 cats, 2 were crewed by couples, the other skipper wasn't married, but did have a married couple aboard as crew.

And the cats, even slowed down for the conditions, did get there faster, and with no bruises on the crew. Almost all the mono sailors had bruises to show for the trip, and some were impressive. And for most of the passage they were wet. We stayed dry. Didn't even get the weather gear">foul weather gear out of the wardrobe.

[Jim Cate]

Originally Posted by 44'cruisingcat

Interesting point. On the Vanuatu trip, not one of the 5 monohulls skipper's wives made the crossing. Not ONE. Of the 3 cats, 2 were crewed by couples, the other skipper wasn't married, but did have a married couple aboard as crew.

And the cats, even slowed down for the conditions, did get there faster, and with no bruises on the crew. Almost all the mono sailors had bruises to show for the trip, and some were impressive. And for most of the passage they were wet. We stayed dry. Didn't even get the foul weather gear out of the wardrobe.

Gee, my admiral has made the trip from New Cal or VAnuatu back to Oz at least a dozen times... what sort of folks do you hang out with?

And FWIW, the return trip is usually a trade wind sleigh ride... all downwind and usually in pretty decent wx conditions. So, in contrast, how did the cats do on the trip TO the islands, which is usually upwind or at least close reaching?

BTW, for monohull scaling factors, we did one trip, Santo to Gladstone, in our previous boat (29 ft LWL) where we averaged (real average here) 159.5 M/day, anchor up to tied to the Customs dock in Gladstone Marina. In our current boat (44 ft LWL) we did Noumea to Bundy averaging 180.0 m/day, again from anchor in Noumea to Customs in Bundy. Only motoring was entering the harbours at the end of the voyages. Both of these passages enjoyed consistent trades 20-25 kts Easterly quadrant. (Actually, the winds at the outset of the first mentioned trip were 30+ now that I think back on it... there was a cyclone threatening to form between Vanuatu and Fiji... hence our pushing the boat a bit harder than usual!) Those ideal conditions don't always bless one, and we've had our share of slower and less comfortable trips on that course.

As I have said before, some cruising cats blow us away off the wind. Many don't seem to, and some are pretty slow. Plenty of differences within each genre...

The lack of significant heel angles is certainly a great feature of cats, but my (admittedly limited) experience of cats at sea is that even downwind there is plenty of motion if there are tradewind type swells with a bit of wind chop on top. The experience is certainly different, may be better for some cruisers, but it is not a panacea for all.

Cheers,

Jim

PS Those two trips were done a few years ago when we were in our late sixties, and without additional crew.

[Captain Jeffry]

Originally Posted by Jim Cate

PS Those two trips were done a few years ago when we were in our late sixties, and without additional crew.

Another great story! Sweet as~

[44'cruisingcat]

This trip was Brisbane to Luganville. Yes, the return trip was much easier. (Mostly because we had much better weather.)

I know plenty of couples cruise, met a lot of them, but for our trip from Brisbane - Luganville, what I stated was the facts.

[Jim Cate]

Originally Posted by 44'cruisingcat

This trip was Brisbane to Luganville. Yes, the return trip was much easier. (Mostly because we had much better weather.)

I know plenty of couples cruise, met a lot of them, but for our trip from Brisbane - Luganville, what I stated was the facts.

Oh, sorry about that! Somehow I got the direction of your subject passage backwards.

Still have to say that my admiral has done all the trips both ways, as well as all the other miles we've cruised.

Cheers,

Jim

[motu42]

We took our 10.6M(36ft) Kelsall catamaran around the Pacific, Aussie and back to NZ a couple of years ago. 6000Nm, all conditions including Tasmania to NZ. We lived aboard for 2 years, so we carried the usual junk. Crew is my wife and I, early 50's and two kids. Usually one extra crew for long passages.(eg 1000+miles)

Max speed (burst) so far is 16knts, Motu is not a racer, but she can move along when pressed.

However I always route planned on 150 miles a day, eg 6knts,which we did actually average. Best was 190Nm day (damn the wind died!). We dont use motor much on passage, as we only carry 48hrs fuel.

We sailed conservatively, faster in daytime, reef early at night, which cost us a bit, but its my family, so I took it easy.

Now with more blue water experience and faith in the boat I would aim at 175 day, but really when you get above 8knts in a 36ft boat its a comfort problem. The conditions you need to get 8knts average, eg 7-10knts baot speed consistently, usually makes chop and unhelpful swell. Cruising becomes enduring. Things wear and break, autopilots struggle.

If you (like us) cruise on a budget and in smaller boats, then use 5knts(100Nm) for a mono, and 6 for a cat.

And each extra knot will cost about 100K :-)

Rob

[Barra]

Originally Posted by motu42

We took our 10.6M(36ft)
And each extra knot will cost about 100K :-)

Rob

Ha ha spot on! that part of the equation often gets lost in discussions like these.

Our boat is no slouch either being a cat from the more performance end of the spectrum but we still plan offshore passages (not coastal hops) on 6.5 knots and looking at boats that would beat that consistently in the real world i think its probably an exponential $ for knot equation from around 8knots up (keeping an acceptable level of crusing comfort)

[zeehag]

i can usually manage 5 kts unless wind is nonexistent or under 10 kts....then add engine we still go 5 kts. the formosa theory, i just made up --formosa my life i will cruise this formosa, so formosa my life, i can pull around 100 miles daily. that is non-mathematically deduced.
is practical and actual. also very accurate.

[marshmat]

As many have already stated, using the "best day's run" as a guide is far too optimistic.

For a rough estimate at the concept design stage, I like to take a guess at an average day's run as follows:

1. Determine approximate top speed. (For a cat, I'll take the minimum of Texel, 'base speed', and the average of traditional hull speed and Gerr's 'corrected' hull speed.)
2. Assume you'll run at 80% of that speed, so as not to be running on the edge, breaking stuff or tossing crew around.
3. Assume you'll make, on average, cos(30) = 0.87 times the distance you'd otherwise calculate, due to tacking, leeway, etc.

The result- about 70% of theoretical top speed- seems to be a good starting point for miles run per day in decent trade wind conditions. In lighter winds, you might start that procedure with 50% to 80% of wind speed, for a reasonably well designed cruising multihull.

[daddle]

For sailors more time at passage is a joy. So speed doesn't matter. It's nice to be able to move along in light air. It's nice if one's boat is sea kindly and fun to sail.

[Captain Jeffry]

Originally Posted by daddle

For sailors more time at passage is a joy. So speed doesn't matter. It's nice to be able to move along in light air. It's nice if one's boat is sea kindly and fun to sail.

Soulfull. Really.

Having said that, I will say that the longer you are offshore, the further you're exposed to changing conditons. Some bad..

[zeehag]

aaaaah, capt jeffrey--but that is the fun of it all---catching fishies and watching for weather and sailing in the seasons not usually associated with bad weather....being ready for the big winds that come on you here off west coast mexico and central america....and watching tortoises sunning and flying fishies sailing just above the seas..

[smuggler]

Having read all the posts in this thread, at the end of the day one doesn't really buy a boat for the daily miles it can "rack up". Daily miles are going to boil down to the budget one has to purchase a boat - within that budget lies the LWL of the purchased boat & therin lies the "theoretical" boatspeed.

The longer the boat - the greater the hull speed. Daily miles will then boil down to the competency and "stamina" of the crew. Can one sustain hours / days of continual concentration ? or will fatigue one to reduce sail & have a snooze ?

I think that in the choice of a boat VJ needs to purchase whatever he can be it muli or mono & get out there & do - experience the "good, the bad & the ugly" and then look to his ideal cruising boat.

Nothing beats "sea miles" in all conditions to direct one to the type of cruising suited to individual situations.

Having owned a multi in a past life (Nautitech 474 that we extended by 2 metres & added 2 metres to the mast because it sailed like a bag), we have gone back to mono. The reasoning here, is as others have pointed out multis have their advantages in certain conditions - however, as a PERSONAL preference I would rather endure heavy weather in a mono. It is what I grew up on and come to feel very comfortable with.

So, my advise to VJ is get out there and do it - get some significant "on the water" experience and then work out what you can do..